Polarographische Bestimmung des Pyridoxols in pharmazeutischen Präparaten

Zusammenfassung Es wird eine neue polarographische Methode zur direkten Bestimmung des Pyridoxols in Injektionspräparaten und Tabletten beschrieben. Die ausgearbeitete Methode beruht auf der polarographischen Reduktion des Pyridoxolmoleküls im Milieu von Ammoniak-Ammoniumchlorid-Puffern und weiter auf der Bildung einer katalytischen Stufe des Pyridoxols in Veronalpuffern. Die polarographische Methode ist rascher und in manchen Fällen genauer und empfindlicher als die bisher in Gebrauch stehenden Methoden. Die Anwesenheit der in den Präparaten laufend vorkommenden Begleitstoffe des Pyridoxols stört nicht die polarographische Bestimmung. Die Methode kann auch zur Bestimmung des 3-Hydroxy-4-methoxymethyl-5-oxymethyl-2-methylpyridins benutzt werden, das ein Zwischenprodukt bei der Pyridoxolerzeugung ist.

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Summary A new polarographic method is described for the direct determination of pyridoxol in injection preparations and tablets. This method is based on the polarographic reduction of the pyridoxol in ammonia-ammonium chloride buffer medium and also on the formation of a catalytic stage of the pyridoxol in veronal buffers. The polarographic method is faster and in many cases more accurate and more sensitive than the methods now in use. The presence of the materials which always accompany the pyridoxol in the preparations does not interfere with the polarographic determination. The method can likewise be used for determining 3-hydroxy-4-methoxymethyl-5-oxymethyl-2-methylpyridine, which is an intermediate product in the manufacture of pyridoxol.

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Résumé On décrit une nouvelle méthode polarographique pour le dosage direct du pyridoxol dans les préparations pour injections et dans les comprimés. La méthode élaborée repose sur la réduction polarographique de la molécule de pyridoxol dans le milieu tampon ammoniaque-chlorure d'ammonium, et, en outre, sur la formation d'une phase catalytique du pyridoxol dans les tampons au véronal. La méthode polarographique est plus rapide et dans de nombreux cas plus exacte et plus sensible que les méthodes utilisées jusqu'ici. La présence d'impuretés existant couramment dans les préparations à côté du pyridoxol ne gêne pas le dosage polarographique. On peut aussi utiliser la méthode pour le dosage de l'hydroxy-3 méthoxyméthyl-4 oxyméthyl-5 méthyl-2 pyridine, substance intermédiaire dans la préparation du pyridoxol.

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Herrn Dr.P. Zuman danken wit für Ratsehläge bei der Abfassung dieser Arbeit.     

Time-resolved fluorescence analysis of the mobile flavin cofactor in p -hydroxybenzoate hydroxylase

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Poly(lactic acid) composites with poly(lactic acid)‐modified carbon nanotubes

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Enhanced downconversion of UV light by resonant scattering of aluminum nanoparticles

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Four-color fluorescence correlation spectroscopy realized in a grating-based detection platform

We have developed a filterless multicolor detection unit for fluorescence correlation spectroscopy (FCS). This grating-based setup is continuously tunable for multicolor separation and is thus a powerful alternative to the classical cascade of dichroic mirrors and filters. Our tailored platform allows for accommodation of up to 15 detection channels covering the entire visible spectral range. As a proof of principle, we successfully demonstrate simultaneous FCS of four distinct fluorescent quantum dot species being mixed in aqueous solution. Grating-based detection allows for spectral high-resolution FCS in a stable and compact setup and is a feasible tool for quantitative investigation of complexbiomolecular dynamics on a single molecule level.     

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